Wash potatoes , pat dry and use a fork to prick all over potatoes. Drizzle some cooking oil and toss to coat well. Bake potatoes in preheated 400°F oven until they just turn soft, about 45 minutes to 1 hour. Remove from the oven. When they are cooled, cut into cubes or strips.

Prepare the roux: melt butter in a small sauce pan on medium heat, add flour and use a balloon whisk to mix together. Whisk constantly until it is aromatic and the roux turns slightly brown. Set aside.

Add little oil in a large pot, saute onion until it turns soft. Add garlic and corn, continue to saute until aromatic. Add chicken broth and water, bring to a boil on high heat. Scoop some liquid to the roux, and whisk the roux to thin it down (it will looks lumpy at first but whisk a few more times then it will be smooth). Add more liquid to roux if necessary.

Pour roux mixture back to the large pot, whisk until the soup has no visible lumps. Add in potatoes, whipping cream, salt and pepper to taste. Garnish with bacon crumbles, green onions, and cheese before serving.